my first interplanetary ship!

[draeath]

I was trying to get a MapSat out to Duna today. I made it very close on the first try. I got excited when I saw I could slingshot off Ike and save myself some time (since I'm using a nuclear reactor and ion engine, fuel is "free"). However, I quickly learned that one should zoom WAAAY in and closely examine the encounter orbits. My teacher? Hearing my probe slam into Ike instead of harmlessly whizzing by! My second try was much more successful.

Note about the engine and "free" fuel - yea, it was hard to get it up there. 300+ ton launch vehicle, intermediate stage about 80 tons. The actual probe? 25! Not much on the probe except for the nuclear reactor, ion engine, and battery... but holey smokes that was heavy. Taking off of Kerbin, there's a spot where I have about 20 seconds before I hit apoapsis while still in a ballistic arc. I catch even about there, and only then start pushing it out ahead of me and gaining orbital velocity. Talk about cutting it close! Not to mention, a single ion engine pushing 25 tons is... slow. Like, really slow. (about 1m/sec ÃŽâ€v)

So, here are some screenies. I realize the 4x NERVA is quite heavy - but as I can get up there with those tanks half-full, those will get me quickly into solar orbit. They are also used (half their fuel goes there...) on the last stage of my ascent, where they have full efficiency (specific impulse of 1100)

The two heavy-lifting stages and SRBs return safely to Kerbin via parachute. The payload nose fairing free-falls back. The nuclear engines nacelles go with me to solar orbit, and are abandoned usually during the mid-course correction to the destination orbital body. The probe does not return (though it does have indefinite delta-V, it's just slow - I could always drop it into the sun or whatnot I suppose).

I know, "eeew MechJeb! Do it yourself!" - I'd be perfectly happy to, provided we had a guidance computer. It's unreasonable to expect one to fly to another planet by the seat of your pants...

Now that is a huge rocket. 128 parts.

Important stats courtesy of Kerbal Engineer Redux. Note that S5 and S3 are detachment stages that use little retro-boosters to help ensure damage-free staging.

Coasting to apoapsis. Note the fairing is gone - exposing the ISA MapSat and MechJeb.

Successful orbit! Got the apsides I wanted and the inclination couldn't be better - I could correct that with RCS, even. Note the before-and-after mass and long time-to-MECO. This is a heavy payload!

The final stage, from Duna's perspective. I have no idea why the coupler sockets are missing from the previous stage. Oh well? The RCS is super useful. You can turn it without, but it feels like a slug.

Edited September 30, 2012 by draeath

[Luxmaster-CZ]

Drag looses over 800? Steering looses over 258!? You did something wrong there. I usually get to orbit with less than 500 in drag looses, and less than 10 in steering looses. Thy playing with your ascent path a little

[draeath]

Check the percentages, not the absolutes. It's heavy and slow so those numbers are ballooned - not once on the way up do I touch terminal velocity. My steering is usually under 2% however the rocket tries to yaw (i think my struts may be crooked. Wish the destination would snap when placing them.)